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Bug #19977

closed

(nil..nil) === x can raise an exception, differing from Range#cover?

Added by kyanagi (Kouhei Yanagita) about 1 year ago. Updated 11 months ago.

Status:
Closed
Assignee:
-
Target version:
-
ruby -v:
ruby 3.3.0dev (2023-10-27T03:13:17Z master f9f0cfe785) [arm64-darwin22]
[ruby-core:115188]

Description

I investigated Range#=== and Range#cover?, and found that the only difference in behavior between them would be that
(nil..nil) === x could throw an exception.

% ~/tmp/ruby-master/bin/ruby -v
ruby 3.3.0dev (2023-10-27T03:13:17Z master f9f0cfe785) [arm64-darwin22]
% ~/tmp/ruby-master/bin/ruby -e 'p (nil..nil) === "a"'
-e:1:in `===': cannot determine inclusion in beginless/endless ranges (TypeError)

p (nil..nil) === "a"
                 ^^^
        from -e:1:in `<main>'
% ~/tmp/ruby-master/bin/ruby -e 'p (nil..nil).cover?("a")'
true

Is this difference intended?

According to NEWS, Range#=== uses cover? since Ruby 2.6 (For String, since Ruby 2.7).

Following this, (nil..nil) === x should not throw an exception in the same way as (nil..nil).cover?(x).

history:

(nil..nil) === "a" throws an exception since https://github.com/ruby/ruby/commit/04a92a6.
For "linear objects" (Integer, Float, Numeric, Time), it has beed fixed not to throw an exception on https://github.com/ruby/ruby/commit/fb17c83.

related issues:

  • [Bug #15449] Range#=== is not using cover in Ruby 2.6
  • [Bug #18580] Range#include? inconsistency for beginless String ranges
  • [Bug #19533] Behavior of ===/include? on a beginless/endless range (nil..nil) changed in ruby 3.2

Updated by kyanagi (Kouhei Yanagita) about 1 year ago

Matz had taken the decision to make (nil..nil) === any_object #=> true in DevMeeting-2023-04-11.
Therefore, we can conclude that this behavior is a bug.

https://github.com/ruby/dev-meeting-log/blob/master/2023/DevMeeting-2023-04-11.md

I created a PR: https://github.com/ruby/ruby/pull/8797

Updated by knu (Akinori MUSHA) 12 months ago

Matz agreed to fix this.

Updated by kyanagi (Kouhei Yanagita) 11 months ago

Can this fix be included in 3.3.0?

Updated by knu (Akinori MUSHA) 11 months ago

I've approved the PR and I'll see if @nobu (Nobuyoshi Nakada) agrees. I definitely would love to see this merged to 3.3.

Actions #6

Updated by kyanagi (Kouhei Yanagita) 11 months ago

  • Status changed from Open to Closed

Applied in changeset git|e8639098ed78f8f8f7c263d8b6f2d68822945a78.


[Bug #19977] Fix (nil..nil) === x not to raise TypeError

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